Centrifuge

ABSTRACT

Centrifuge for separating liquid and solid components from a suspension, wherein the centrifuge is provided with a centrifugal drum and a filter bag insertable therein. A boundary edge of the filter bag is attached to the discharge end of the centrifugal drum and the other boundary edge is attached to a mushroom-shaped or buffer-type bottom piece; the centrifugal drum and the bottom piece are arranged coaxially with respect to each other and are rotatable together. In addition, the drum and bottom piece are relatively axially movable with respect to each other during rotation. A lid is mounted to the bottom piece and contacts the discharge end of the drum when the bottom piece is located at the bottom of the centrifugal drum during the centrifuging process itself. The lateral walls of the centrifugal drum are tapered conically to a minor extent toward the bottom at an angle which allows removal of the centrifugal drum from the filter bag in a satisfactory and easy manner.

United States Patent 72] Inventor Johann P. Quetach Berghausen, Germany[2!] Appl. No. [6,337 [22] Filed Mar. 4. I970 [45] Patented Nov. 30.I971 [73] Assignee Ernst Helnkel Maaclllnenbau Gmbll Stuttgart, Germany[32] Priority Mar. 5, 1969 Germany [3|] I'I9ltl47.8

[54] CENTRIFUGE 0 Claims, 2 Drawlng Flgs.

[52] U.S. Cl d. 210/370 [51] lnt.Cl t t y i 801d 53/00 50] FieldolSearcli H 2l0/237. 370, 356

[56] References Cited UNITED STATES PATENTS 3,438,500 4/l969 Pico210/237 X Primary Examiner- Reuben Friedman Assistant Examiner-CharlesN. Hart Attorney-Craig, Antonelli 8; Hill ABSTRACT: Centrifuge forseparating liquid and solid components from a suspension, wherein thecentrifuge is provided with a centrifugal drum and a filter baginsertable therein. A boundary edge of the filter bag is attached to thedischarge end of the centrifugal drum and the other boundary edge isattached to a mushroom-shaped or buffer-type bottom piece; thecentrifugal drum and the bottom piece are arranged coaxially withrespect to each other and are rotatable together. In addition. the drumand bottom piece are relatively axially movable with respect to eachother during rotation. A lid is mounted to the bottom piece and contactsthe discharge end of the drum when the bottom piece is located at thebottom of the centrifugal drum during the centrifuging process itselfThe lateral walls of the centrifugal drum are tapered conically to aminor extent toward the bottom at an angle which allows removal of thecentrifugal drum from the filter bag in a satisfactory and easy mannerPATENTEmuv 30 I9?! SHEET 1 [IF 2 INVENTOR J HIJNN A) II crsrvrruruor:

BACKGROUND OF THE INVENTION The present invention relates to acentrifuge capable of separating solid and liquid components from asuspension, and more particularly to a centrifuge with a perforatedcentrifugal drum or basket and a filter bag insertable therein. Oneboundary edge of this filter bag is attached to the discharge end, whichis preferably flange-shaped, of the centrifugal drum and the otherboundary edge of this filter bag is affixed to a mushroom-shaped orbuffer-type bottom piece. The centrifugal drum and the bottom piece arearranged coaxially with respect to each other and can be put intorotation together, and can be subjected to an axial relative motion withrespect to each other during this rotation.

In the conventional pendulum centrifuges preferably employed for thetreatment of suspensions having extremely fine solid components, theremoval of the centrifugate or centrifuge cake must be effected eidiermanually or by means ofa clearing device in the lid of the centrifugaldrum, i.e., top discharge, or in the bottom, i.e., bottom discharge.

However, all types of discharging processes are problematic when theproducts to be treated have a tendency to cement after thehydroextraction step and can be discharged only under the greatestdifficulties. In this procedure, but also in the case of well-behaved"substances, the filter bags are very often damaged and become unusable.Under certain circumstances, the structure of sensitive material can bedamaged during a mechanical discharging operation.

The peeling or paring centrifuges likewise employed heretofore for theseparation of solid and liquid components exhibit the disadvantage thatthey cannot completely remove the centrifuged solid material. Thepeeling device, which can be adapted with respect to its clearing speedto the material properties present in each particular case, alwaysleaves a residual layer on the filter. This layer becomes denser andharder with each operating cycle, thus causing conditions which becomeworse from charge to charge. Furthermore, the filter element can easilybe damaged by the peeling device, in addition to the damage which can becaused by the disassembly necessary for the required cleaning of thefilter insert, and during the sub sequent rinsing operation.

SUMMARY OF THE INVENTION It is an aim of the present invention to avoidthe aforementioned problems and disadvantages and to provide acentrifuge which has a simpler construction as compared to peelingcentrifuges and pendulum centrifuges with automatic removal.

Furthermore, the present invention also aims at solving the separatingproblems which, by the use of the above-mentioned conventionalcentrifuges, could not be overcome or which pennitted onlyunsatisfactory results at best. Additionally, it is an object of thepresent invention to provide a centrifuge which permits a utilization inmany boundary cases wherein previously only filter presses could beemployed and which filter presses are much more expensive than thedevice of the present invention.

It is another object of the present invention to provide a centrifuge,use of which affords great savings, a greater efficiency per time unit,and the elimination of manual operating steps.

The underlying problems are solved in accordance with the presentinvention by mounting a lid to the bottom piece, particularly by way ofconnecting members, which lid contacts the discharge flange of thecentrifugal drum, when the bottom piece is disposed at the bottom of thecentrifugal drum as provided during the centrifuging process proper. Thedrum is axially displaceable for the purpose of discharging, whereasduring this procedure the bottom piece with the lid, at least at first,maintains an unchanged position with respect to parts of thecentrifugate formed during the centrifuging.

In another suitable embodiment in accordance with the present invention,the connecting members can consist of at least two pins or bolts or thelike, the length of which is approximately equal to the difierence ofthe inner depth of the centrifugal drum and the thickness of the bottompiece. In addition, the lid can be provided with a gasket or sealpreferably inserted in an annular groove, which gasket contacts thedischarge flange of the centrifugal drum when the bottom piece isdisposed at the bottom of the centrifugal drum.

In order to fill the centrifugal drum, the lid can be provided with acentral opening into which a fill pipe or feedpipe and, optionally, alsoa pressure pipe extend, which pressure pipe is used for supplyingwashing fluid and has apertures extending at right angles to the axis ofthe centrifugal drum; these aper tures are oriented toward the peripheryof the centrifugal drum.

In order to readily remove the centrifugate after the termination of thecentrifuging step, from the centrifugal drum, the lateral walls of thedrum are tapered conically to a minor extend or degree toward the bottomat an angle which is of such a magnitude that the removal of thecentrifugal drum from the filter bag can still be accomplished in asatisfactory and easy manner.

Furthermore, the centrifugal drum can be axially displaced approximatelyby twice the length thereof and can be seated on a hollow shaft, whichis connected to the stem of the bottom piece extending into the hollowshaft. This connection is effected by means of at least two keys.Thereby, the hollow shaft and, consequently, also the centrifugal drumcan be driven at the same speed as the stem of the bottom piece and thusthe bottom piece proper. In this connection, the hollow shaft can bedisplaced with respect to the stem in the axial direction of the latter.

The centrifuge can best be driven by way of the nondisplaceable stem.Thus, this stem represents the drive shaft cf fecting the entrainment ofthe hollow shaft, on which the centrifugal drum is seated, by means ofthe keys. However, these keys still permit the displacement of the,hollow shaft with the centrifugal drum even during the driving thereofin the longitudinal or axial direction of the shaft for the purposeofemptying the filter bag.

BRIEF DESCRIPTION OF THE DRAWING These and further objects, features andadvantages of the present invention will become more apparent from thefollowing description when taken in conjunction with the accompanyingdrawing which shows, for purposes of illustration only, an embodiment inaccordance with the present invention, and wherein:

F IG. 1 is a partial sectional view of the centrifuge; and

FIG. 2 is an enlarged section through part of the centrifuge with thefilter drum.

DETAILED DESCRIPTION OF THE DRAWING Referring now to the drawings, andin particular, to FIG. I, the centrifuge in accordance with the presentinvention is disposed in a housing 1. A sleeve or bushing member 2 ismounted in an axially displaceable manner in housing 1, but is securedagainst rotation by means of keys 3 engaging in corresponding grooves inthe housing I and in grooves in the sleeve. In the sleeve 2, a hollowshaft 4 with three bearings S is disposed. The bearings rotate withinthe sleeve 2, and can be axially displaced together with the sleeve. Inthe hollow shaft 4, in turn, the stem 6 of a mushroom-shaped orbuffer-type bottom piece 7 is disposed and the hollow shaft 4 is mountedto be displaceable with respect to the bottom piece 7. The hollow shaft4 and the stem 6 of the bottom piece 7 are secured against mutualrotation by means of keys 8. The stem 6 of the mushroom-shaped orbuffertype bottom piece '1 simultaneously serves as the drive shaft andthus is provided with a V- belt pulley 9 driven via the V-belts II by amotor 12 seated on a bracket 13 attached to the housing at the end ofthe stem 6 facing away from the bottom piece 7.

At the free end of the sleeve 2, a chamber 14 is arranged which can beaxially displaced together with the sleeve 2, but the chamber is notrotatable. This chamber 14 is in communication with a drainpipe 15 forthe discharge of the centrifuged liquid.

On a steplike widened portion of the hollow shaft 4, a perforatedcentrifugal drum 16 is disposed and rotates together with the hollowshaft 4 as well as being displaceable together with the shaft in thelongitudinal direction of its axis. A filter bag 17 is inserted in theperforated centrifugal drum [6. One boundary edge 18 of this filter bagis attached to the flangelike discharge end 19 of the centrifugal drumand the other boundary edge 21 thereof is affixed to the mushroomshapedor buffer-type bottom piece 7. In addition, a lid 23 is attached to thebottom piece 7 by means of connecting members fashioned, for example, aspins or bolts 22. The connecting members or pins have a length which isapproximately equal to the difference between the inner depth D of thecentrifugal drum 16 and the thickness T of the bottom piece.Accordingly, the lid 23 contacts the flangelike discharge end of theaxially displaceable centrifugal drum [6 when the bottom piece 7 isdisposed at the bottom 24 of the centrifugal drum 16 as provided duringthe centrifuging process proper.

The lid 23 has a central opening 25 into which a fill pipe 26 extends.Furthermore, a washing pipe 27 is extended into the central opening 25of the lid 23, which washing pipe has apertures 28 extending at rightangles to the axis of the centrifugal drum. Through these apertures 28,a washing liquid can be sprayed when the centrifugate 29 is additionallyto be treated with an appropriate washing liquid after the centrifugingstep. The lid 23 furthermore is provided with an annular groove intowhich a gasket or seal 31 is placed. This gasket contacts the dischargeflange 19 of the centrifugal drum I6.

The lateral walls of the centrifugal drum l6 taper conically to a minorextent to degree toward the bottom. The taper is provided at such anangle which still barely permits the satisfactory withdrawal of thecentrifugal drum from the filter bag 17. In the case of too large aninclination of the lateral sur' faces of the centrifugal drum, theindividual parts of the filter bag are put under too great a stress as aconsequence during the discharging thereof. With a cylindrical extensionof the lateral surfaces, the withdrawal of the centrifugal drum from thefilter bag would become too difficult and the drum would be damagedunder certain circumstances, such as is also the case, when the lateralsurfaces of the centrifugal drum have too large an inclination.

The displacement of the centrifugal drum in the axial directionapproximately corresponds to twice the length thereof, so that thefilter bag can be completely inverted.

The operation of the centrifugal drum proper takes place as follows: Thecentrifugal drum, that is the centrifugal basket 16 and the filter bag17, are driven by way of the stem 6, that is the drive shaft of themushroom-shaped or bufferlike bottom piece 7; by means of the connectingmembers 22, the lid 23 is likewise rotated. The centrifugal drum and thelid rotate together, as illustrated in full lines in FIGS. 1 and 2, andin such a manner that the lid 23 contacts, along with gasket 31, thedischarge flange 19. By means of the fill pipe 26, the suspension to beseparated is filled in metered amounts through the lid opening 25 intothe centrifugal drum wherein the filter bag is disposed. After thetermination of the filling procedure, a feed valve disposed in thefilling pipe (not shown) is shutoff, and the dmm is maintained inrotation until the desired residual moisture is attained. During thecentrifugation process, the centrifuged liquid flows, via the chamber 14and the drainpipe 15, into a filtrate trap (not shown) intended for theliquid. A washing process can follow thereafter, wherein a preselectedliquid is fed through the washing pipe 27, which liquid is sprayed ontothe centrifugate cake 29 through the apertures 28. After this liquid haslikewise been removed by centrifuging, the centrifugal drum is placed,together with the sleeve 2, into the position shown in dot-dash lines inFIGS. 1 and 2 by shifting the hollow shaft 4. Due to the conical shapeof the centrifugal drum, the centrifugal basket can readily be pulledoff the filter bag and the centrifugate. In this procedure, the filterbag is gradually inverted more and more toward the outside, startingwith its upper end, in correspondence with the path of the centrifugaldrum and thus releases, starting with the lid 23 and continuing towardthe bottom piece 7, one portion after the other of the filter cake,which latter is thereby fiung into the space 32 formed by the housing 1and is removed therefrom. At the end of the axial movement of thecentrifugal basket 16, the filter bag 17, which is attached to thedischarge end 19 of the centrifugal basket and at the bottom piece 7,has been inverted toward the outside along its entire breadth with itsinternal operating surface. Thus, under the efiect of the rotation ofall parts, the entire amount of solid material has then been centrifugedinto the chamber 32 intended therefor.

After this procedure is terminated, the centrifugal basket is againplaced into its starting position, the filter bag retreating into thecentrifugal drum. Upon abutment of the discharge flange 19 of thecentrifugal drum against the gasket 31, the lid 23 seals the centrifugalbasket.

The above-described operating cycle takes place with hydraulic orpneumatic regulation. For this control step which entails shifting ofthe hollow shaft 4, conduit systems are pro vided, of which the conduitsections 33, 34 and 35 are illustrated in FIG. I, and a pump 36 islikewise arranged for this purpose.

In the present invention, the filter insert is pulled off from thematerial and inverted; the material, during the rotation, is removed bycentrifugation from the filter insert without leaving any residuethereon and is disposed in a space provided for this purpose. Noresidual layer remains on the filter, and the disadvantages incurredthereby, as well as any damage to the filter by the peeling blade, areavoided.

While I have shown and described one embodiment in accordance with thepresent invention, it is to be clearly undersiood that the same issusceptible to numerous changes and modifications as will be apparent toa person skilled in the art, and 1, therefore, do not wish to be limitedto the details shown and described herein but intend to cover all suchchanges and modifications that are encompassed by the scope of thepresent invention.

I claim:

I. Centrifuge adapted to separate solid and liquid components of asuspension, comprising:

a housing;

perforated centrifugal drum means rotatably mounted in said housing andhaving a flanged-shaped discharge end;

means for rotating said centrifugal drum means;

bottom means coaxially arranged and operatively associated with respectto said centrifugal drum means and rotatable therewith, said bottommeans being in a fixed axial position relative to said housing;

said centrifugal drum means and said bottom means being axially movablewith respect to each other;

filter bag means insertable in said centrifugal drum means, having firstand second boundary portions operatively connected to said discharge endof said centrifugal drum means and said bottom means, respectively;

lid means arranged at the discharge end of said centrifugal drum meansand operatively associated with said bottom means;

said centrifuge constructed so that for purposes of discharging, saidcentrifugal drum means is axially displaced while said bottom means ifretained in a relatively fixed position along with said lid means withrespect to centrifugate portions formed during the centrifuging process.

2. Centrifuge according to claim I, which further comprises connectingmembers joining said bottom means and said lid means, said connectingmembers including at least two bolts, the length of each beingapproximately equal to the difference resulting from the inner depth ofthe centrifugal drum means and the thickness of the bottom means.

3. Centrifuge according to claim 1, wherein said lid means is providedwith a gasket means inserted in an annular groove thereof, said gasketmeans adapted to sealably contact said discharge end of said centrifugaldrum means when said bottom means and said centrifugal drum means arejuxtaposed.

4. Centrifuge according to claim I, wherein a fill pipe means isprovided for feeding said suspension to said centrifugal drum means,said fill pipe means extending into a central opening in said lid means.

5. Centrifuge according to claim 4, wherein a washing pipe means isprovided and extends into a central opening of said lid means forfurther treating the centrifugate, said washing pipe means beingprovided with apertures extending at substantially right angles to theaxis of said centrifugal drum means.

6. Centrifuge according to claim I, wherein said centrifugal drum meansincludes lateral wall portions which taper conically to a minor degreetoward the bottom at an angle such that said centrifugal drum means canbe withdrawn satisfactorily from said filter bag means.

7. Centrifuge according to claim 1, wherein said centrifugal drum meansis axially displaceable by approximately twice its axial length.

8. Centrifuge according to claim I, wherein a hollow shaft is operablyconnected by key means with a portion of said bottom means extendinginto said hollow shaft, said centrifugal drum means being seated on saidhollow shaft.

0 i i i Q

1. Centrifuge adapted to separate solid and liquid components of asuspension, comprising: a housing; perforated centrifugal drum meansrotatably mounted in said housing and having a flanged-shaped dischargeend; means for rotating said centrifugal drum means; bottom meanscoaxially arranged and operatively associated with respect to saidcentrifugal drum means and rotatable therewith, said bottom means beingin a fixed axial position relative to said housing; said centrifugaldrum means and said bottom means being axially movable with respect toeach other; filter bag means insertable in said centrifugal drum means,having first and second boundary portions operatively connected to saiddischarge end of said centrifugal drum means and said bottom means,respectively; lid means arranged at the discharge end of saidcentrifugal drum means and operatively associated with said bottommeans; said centrifuge constructed so that for purposes of discharging,said centrifugal drum means is axially displaced while said bottom meansis retained in a relatively fixed position along with said lid meanswith respect to centrifugate portions formed during the centrifugingprocess.
 2. Centrifuge according to claim 1, which further comprisesconnecting members joining said bottom means and said lid means, saidconnecting members including at least two bolts, the length of eachbeing approximately equal to the difference resulting from the innerdepth of the centrifugal drum means and the thickness of the bottommeans.
 3. Centrifuge according to claim 1, wherein said lid means isprovided with a gasket means inserted in an annular groove thereof, saidgasket means adapted to sealably contact said discharge end of saidcentrifugal drum means when said bottom means and said centrifugal drummeans are juxtaposed.
 4. Centrifuge according to claim 1, wherein a fillpipe means is provided for feeding said suspension to said centrifugaldrum means, said fill pipe means extending into a central opening insaid lid means.
 5. Centrifuge according to claim 4, wherein a washingpipe means is provided and extends into a central opening of said lidmeans for further treating the centrifugate, said washing pipe meansbeing provided with apertures extending at substantially right angles tothe axis of said centrifugal drum means.
 6. Centrifuge according toclaim 1, wherein said centrifugal drum means includes lateral wallportions which taper conically to a minor degree toward the bottom at anangle such that said centrifugal drum means can be withdrawnsatisfactorily from said filter bag means.
 7. Centrifuge according toclaim 1, wherein said centrifugal drum means is axially displaceable byapproximately twice its axial length.
 8. Centrifuge according to claim1, wherein a hollow shaft is operably connected by key means with aportion of said bottom means extending into said hollow shaft, saidcentrifugal drum means being seated on said hollow shaft.